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Filtration Water Treatment

Municipal Water Supply

  1. Rasheed Ahmad

Published Online: 15 JUL 2005

DOI: 10.1002/047147844X.mw96

Water Encyclopedia

Water Encyclopedia

How to Cite

Ahmad, R. 2005. Filtration Water Treatment. Water Encyclopedia. 1:245–248.

Author Information

  1. Khafra Engineering Consultants, Atlanta, Georgia

Publication History

  1. Published Online: 15 JUL 2005


Filtration systems employed at water treatment facilities use a porous medium through which water passes to remove suspended solids. A number of methods have been developed to meet this objective. Currently, rapid gravity filtration is the most commonly used filtration technology in developed countries for drinking water treatment. However, developments in filtration technology have increased the popularity of the other types of filtration systems. Filters can be classified into different types depending on the rate of flow (e.g., rapid sand and slow sand filters), media (single and dual media filters), hydraulic arrangement (gravity and pressure filters), direction of flow (up-flow and down-flow filters), and removal depth (cake and deep filters). The two most common types of filtration system used in water treatment are gravity filtration and pressure filtration. The gravity filtration system has two major types: rapid gravity filtration and slow sand filtration. The pressure filtration system commonly consists of four types: rapid rate pressure filtration, diatomaceous earth filtration, membrane filtration, and cartridge filtration.


  • backwashing;
  • biological filters;
  • cartridge filters;
  • diatomaceous earth filtration;
  • direct filtration;
  • filtration;
  • granular media filtration;
  • membrane filtration;
  • particulate removal;
  • precoat filtration;
  • pressure filters;
  • rapid sand filter;
  • schmutzdecke layer;
  • slow sand filter;
  • turbidity